making nio use kevent/kqueue

[Vlad GALU]

On 8/23/07, Nick Johnson <freebsd at spatula.net> wrote:
> Looking at it a bit more, it looks like the "right" thing to do is to
> create a KeventArrayWrapper, possibly based on the EPollArrayWrapper.c so
> that multiple ready FDs can be returned at one time.
>
> That means creating a KeventArrayWrapper.java based on
> j2se/src/solaris/classes/sun/nio/ch/EPollArrayWrapper.java as well as a
> KeventSelectorImpl.java based on EPollSelectorImpl.java and
> KeventSelectorProvider.java based on EPollSelectorProvider.java.
>
> It also means modifying
> src/solaris/classes/sun/nio/ch/DefaultSelectorProvider.java to select the
> KeventSelectorProvider and possibly tweaking some makefiles to ensure that
> everything gets built, including:
>
> make/java/nio/Makefile
> make/java/nio/mapfile*  (do we end up using mapfile-linux or
> mapfile-solaris?)
>
>    Nick
>
> On Thu, 23 Aug 2007, Nick Johnson wrote:
>
> > I think there could be a considerable performance gain if java.nio were
> > tweaked to use kevent/kqueue(2) as opposed to poll(2).
> >
> > It looks like the files that would need to be touched for this are:
> >
> > j2se/src/solaris/native/sun/nio/ch/
> >       DevPollArrayWrapper.c  (not sure about this one actually since
> > FreeBSD doesn't use /dev/poll)
> >       PollArrayWrapper.c
> >       SocketChannelImpl.c
> >
> > Does that sound about right?  I see select(2) and poll(2) used in other
> > places as well, though outside of nio where they're likely to show the
> > greatest benefit.
> >
> > Are there any caveats or "gotchas" I should be aware if should I decide to
> > take some free time to try to come up with a kevent patch for nio?
> >
> > Also, is there a quicker way to build a JVM when just changing a file or
> > two like this?  It would be lousy to have to wait 2 hours to build after
> > every minor change...

    IIRC, the OS-X Java uses kqueue already. Furthermore, classpath
(http://www.gnu.org/software/classpath/) supposedly has a kqueue nio
implementation. I haven't tried any of the two aforementioned
solutions, but it's definitely something I'll want to take a look at
in the near future.

    HTH :)

> >
> >    Nick
> >
> >
>
> --
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>  afraid and doing what you have to do anyway."
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